Hearing aids and other portable audio devices often use Class D output drivers due to their high power efficiencies. Since the output signal of an output driver is directly modulated by the supply voltage, this voltage should be free of disturbances. In hearing aids and other portable audio devices, this may not be possible as the power supply is often a small battery, which is also used to power circuits with a non-constant current load such as a wireless transmitter/receiver or a microphone. If such a variable current draw is active, it can cause the battery voltage to vary over time and thus produce fluctuations. One consequence is that the audio performance of the output driver can degrade significantly. A person wearing such a device may hear unwanted abrupt variations in volume, clicks, or other noises. Adding filtering components or a larger battery to a portable audio device negatively affects size, portability, and wearability.